Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover read-only/idempotent/non-destructive safety, so the bar is lower, and the description adds useful context: synchronous execution, task support forbidden, and that it does not persist to Studio. It omits operational traits like scraping/browser-fetch latency, failures on unreachable URLs, or rate limits for the open-world fetch.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.